Skip to content

Channel Routing

Overview

Channel routing tab in miniDSP Flex HT

The Channel Routing tab is the first of two matrix mixers. This mixer has 9 inputs: the eight speaker channels (optionally high pass filtered) and the output from the Bass Mgmt tab. The mixer outputs connect to the eight channels of Dirac Live processing.

Bass routing with default routing for the miniDSP Flex HT

Each input to the mixer can be routed to any of the mixer outputs. Each input (down the left) can be routed to more than one output (along the top). If more than one input is routed to a given output, they are summed together.

Examples

This section contains several basic examples illustrating how to use the Channel Routing mixer. In a real application, you will often want to combine these examples in various ways (for example, to use bass management as well as upmixing).

Direct playback

To illustrate the routing examples, we will use the signal flow diagram overlaid with blue to indicate where signal flows for that particular example. The diagram below shows the "straight through" routing. This is the default routing set by the matrix shown above.

Routing for direct playback in miniDSP Flex HT

Bass management

The diagram below shows the signal flow for bass management, simplified to show only the front left and right speaker channels:

Signal flow for bass management in miniDSP Flex HT

  • The Bass Mgmt block creates an extra signal that contains the low frequencies from the speaker channels, summed with the LFE input channel.
  • The Channel Routing block must route this signal to the subwoofer. Assuming the subwoofer is connected to channel 3, the channel routing matrix is as shown below.

Routing for bass management in miniDSP Flex HT

Upmixing

Upmixing refers to routing a channel to more than one output channel. The figure below shows the signal flow for a simple case of upmixing. In the case where you have 7 speaker channels but the source material only has five channels, the surround channels can be upmixed to the rear channels:

Signal flow for channel upmixing in miniDSP Flex HT

This is the channel routing matrix for this example:

Routing for upmixing in miniDSP Flex HT

Note that upmixing should be done in the first mixer, Channel Routing, and not in the second mixer, Matrix Mixer.

Downmixing

Downmixing refers to mixing more than one input channel to a single output channel. The figure below shows the signal flow for a simple case of downmixing. In the case where you have 5 speaker channels but the source material has seven channels, the rear surround channels can be downmixed to the left and right surrounds:

Signal flow for channel downmixing in miniDSP Flex HT

This is the channel routing matrix for this example:

Routing for downmixing in miniDSP Flex HT

Note that downmixing should be done in the first mixer, Channel Routing, and not in the second mixer, Matrix Mixer.

Surround sound synthesis

The channel mixer can be used to perform basic surround sound synthesis. For example, this figure illustrates the signal flow when surround channels are synthesized from the front left and right channels:

Signal flow for surround synthesis in miniDSP Flex HT

In this example, the left surround channel is synthesized by taking the left front channel and subtracting the right front channel from it. Similarly, the right surround channel is synthesized by taking the right front channel and subtracting the left front channel from it.

This is the channel routing matrix for this example:

Routing for surround synthesis in miniDSP Flex HT